Improvement in variable cut-offs for steam-engines



UNITED STATES PATENT Orrrcnl WILLIAM WRIGHT, on NEW YORK, N. Y.

IMPROVEMENT IN VARIABLE CUT-OFFS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 139,224, dated May 20,1 .873; application filed V January 4, 1873.

To all whom it may concern:

Be it known that I, WILLIAM WRIGHT, of the city, county and State of NewYork, have invented an Improvement in Variable Cut- Oft's forSteam-Engines, of which the followin g is a specification:

This invention relates to the engine cut-offs, controllable by thegovernor, and in which the cut-off valves, that may also be theinduction ones, are actuated by a variable tappet motion. The inventionconsists in a combination of peculiarly. constructed and reverselyarranged vibrating valve-lifters, also capable of longitudinal motionrelatively with the axis tion-valves, one to each end of the cylinderand both of grid construction, although they may be of any othersuitable description, it only being important, so far as the novelty ofthis invention is concerned, that each valve is independent of the otherand that they are capable of being separately lifted and of beingsuddenly dropped to let steam on to opposite ends of the cylinder, andto out it off therefrom at difi'erent points in the stroke of thepiston. G U are the exhaust-valves of the engine. These valves, whichmay also be grid ones, are operated by a longitudinally reciprocatingrod, b, deriving its motion from a crank or arm, 0, fast to arock-shaft, d, which is vibrated by a lever, e, that receives its motionby an eccentric from the main shaft of the engine. The same eccentricactuates both the induction and exhaust valves; but, while the latterhave a positive motion, that is-have no variable action-theinduction-valves are capable of a variable action, subject to thecontrol of the governor. Thus, on the rock-shaft d is an arm, f, whichhas pivoted to it a link,

g, that is cross-jointed to an arm, h, on a shaft,

B, arranged to run longitudinally along the side of the engine. Thisshaft is capable both of a rocking motion in its bearings '13 t, and ofa longitudinal or sliding movement therein.

Said shaft D has upon it the lifters E E, which B B earlier or later inthe stroke, according to the work demanded of the engine. The axiallines of the valve-stems l l are here repre sented as intersecting theaxial line of the rock-shaft D; but this is not a necessary arrangement,inasmuch as said stems might be laterally arranged in relation with. theshaft; but in any case the lifters E E are arranged on reverse sides ofthe rock-shaft D to alternate the action of the valves. The rockingmotion of the shaft D is continuous, but its longitudi nal movement isrestricted to variations in the cut-off action of the valves B B. Toinsure a perfect and desirable action of the lifters E E and of certainjointed toe-piecesm m, attached to the toes F F on the valve-stems, bywhich the lifters operate the valves B B, each of said lifters isconstructed as follows: They are not simply eccentric to the shaft D,but are oblique in direction of their length along their outer or actingedge it, relatively to the axial line of the shaft D, and said outeredge of a spiral configuration lengthwise of the lifter upon atransversely-curved upper surface of said edge struck from a center orcenters which bears a lateral relation to the shaft D. The.

throughout their whole width toor as they leave the outer sharp edge ofthe lifters. The obliquity and pitch of the acting surfaces at of thelifters E determine the sensibility ofthe cut-off.

In the operation of the cut-off, the rocking motion of the shaft Dcauses thelifters E E to alternately lift the valve B B, and thereby toadmit steam alternately to opposite ends of the engine cylinder, but assoon as the acting edges n of the lifters pass from under the pieces m,the period of which, in the stroke of the engine, will be determlned bythe longitudinal adjustment of the shaft D and its attached lifters, thevalves B B, drop and cut off further supply of steam to the engine. Anysuitable cushioning means may be used for easing the drop of saidvalves.

, What is here claimed and desired to be secured by Letters Patent, is

WM. WRIGHT.

Witnesses.

HENRY T. BROWN, MICHAEL RYAN.

